Are you sure you want to continue to do that? Long term probably not, short term yes I want the existing broken one replaced with something that fits what is already there. I don't want to have to drill any new holes for attachment or anything until I learn a little more and actually get to camp in it.

Marinco makes a different style which is completely sealed. Google it to see what it looks like. (Yes is VERY different) Marinco makes a lot of things which one is what you have?

Unless you have an a/c unit, I too would also opt to get rid of the existing shore cable and port and convert to a 15 amp flush plug-in connector. Advantages include:
1. One less entry point for critters and water
2. The shore cord robs you of cabinet space, you can keep a removeable cable anywhere you want, even in your tow vehicle.
3. If you accidently drive off with the cord still plugged in it will just disconnect with minimal damage.
If the RV dealers in Coos Bay don't have what you need, try the several boat shops thereabouts.